Expansion-shield.



Nu. 685,820. Patented Nov. 5, |901.

J. H. cook.

EXPANSION SHIELD.

(Application led Mar. 7, 1901.)

(No Modal.)

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. shield, as indicated in Fig. l.

UNITED STATES PATENT OEEICE.

-JOHN H. COOK, OF BROOKLYN, NEW YORK, ASSIGNOR TO HENRY B. NEVVHALL, OF PLAINFIELD, NEV JERSEY.

EXPANSION-SHIELD.'

SPECIFICATION forming part of Letters Patent No. 685,820, dated November 5, 1901.

Application tiled March 7, 1901.

To @ZZ whom it may concern:

Be it known that I, JOHN H. COOK, a citizen of the United States, residing in the city of New York, borough of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Expansion-Shields, of which the following is a specification, reference being had to the drawings accompanying and forming part of the same.

My present invention relates to expansionshields by which a threaded bolt is adapted to be secured to marble, slate, tiling, or other fragile material by being forced into such an expansion-shield fitted into a hole in such material.

Referring to the accompanying drawings, in which similar reference-letters refer to like parts throughout the various views, Figure l is a longitudinal axial sectional view taken on the lines c of Figs. 2 and 3. Fig. 2is an elevation of the slotted end of my shield. Fig. 3 is an elevation of the opposite end or head. Fig. 4 is a view in perspective, part of my shield being shown broken away, so as to indicate the shield as expanded by a threaded bolt. Fig. 5 is another perspective view of my shield beforeit has been expanded.

I prefer to construct my expansion-shield out of some soft ductile material, so that the parts thereof may readily bend or yield under the action of a bolt engaging the same. The body of the shield,which is preferably formed by casting it in one piece, has a substantially cylindrical contour and is formed with a tapering hole D of square cross-section, as is indicated in Figs. l, 2, and 3. A series of longitudinal slot-s c are formed so as to extend throughout a greater portion of the length of the shield, such slots being formed in that end of the shield which has the smallest axial cavity-that is, the left end of the As is seen in Figs. 2 and 3, these slots extend substantially parallel to the sides of the axial hole D, so that the interior projections are formed at the end opposite to the head A of the shield by the intersection of two adjacent longitudinal slots c in connection with the axial hole D, so that small longitudinal grooves b are formed on the interior of the members or sec- Serial No. 50,159. (No model.)

tions B, each of which is attached to the tubular head A of the shield. The members or sections B are of varying radial thickness throughout the length of the shield. As is seen in Fig. 1 of the drawings, these niembers have a greater thickness at the left end or the inner end of the shield as the same is inserted in a cavity. It will be understood, of course, that the amount of variation in the radial thickness of the members or sections B throughout the length of theshield may differ considerably from what I have shown in Fig. 1 of the drawings. The greater this variation in radial thickness at the two ends of l the shield the more pronounced will be the dovetail action of the shield in gripping t-he material in which it is placed. Each one of these members or sections B is adapted to yield under the action of any radial pressure and can move with sufficient freedom with respect to the tubular head A.

The external cylindrical surface of this shield is preferably roughened, so that it will engage more effectively with any material into which it is inserted.

The action of my shield is as follows: The shield is inserted into a cylindrical hole made in any material-'such as wood, marble, brick, or tiling-gto which it is desired to secure a bolt. The shield is inserted into the hole, in which it preferablyV I'its rather loosely, and engages the material just sufficiently to hold it in place, the head A being outward. A screw-bolt is then inserted into the cavity'D of the head of the shield and is driven down through such cavity, and its threads engage the projections formed on the members or sections B and on the interior of the square hole D, into which the threads of the screw readily bite and render it easy to drive such screw in. The threads of the screw engage with the interior of my shield through only a small portion of the periphery of such screw,

since, as is ndicated in Fig. 2, the ribs or projections extend over a small portion of the interior surface of the shield, Where they would engage a screw inserted into the shield to form a seat or support for the screw. Since the screw or bolt engages the interior of the shield, and especially the grooves b, in this manner, it grips them positively, since it IOC quickly cuts in to the full depth of the screw and 'alsopforces the said members or sections B out radially with a yielding pressure, so that they engage the walls of the cavity into which the shield has been inserted throughout substantially the Whole periphery of such cavity, and yet they are not forced outward with any excessive pressure such as would be likely to fracture even the most delicate or fragile material. Since the members or sections B are of varying radial thickness, as has been described, these members are forced outward with greater pressure at the rear end of the shield-that is, at the free end of these members or sections B-than at the portions of such members or sections near the head of the shield. The expansion-shield therefore grips the material into which it is inserted more firmly at the bottom of the hole than it does at the top, and if the material into which the shield is inserted is at all yielding a dovetail action will take place which will hold the shield and the screw firmly embedded in the same with great rigidity.

My expansion-shield is adapted to grip the material into which itis inserted alllhe more readily because of the slight project ions which are formed upon the exterior cylindrical surface of my shield, as indicated in the drawings, since these projections formed inthe soft material of which the shieldis composed are forced outward with such pressure that they conform to any slight variations in surface in the inside of the hole in which the shield is placed more readily than a shield having a smooth cylindrical surface could do. The slight longitudinal grooves b, formed on the inside of the ribs of the members or sections B, are adapted to guide the screw or bolt inserted into the shield in amoreaccurate manner, since by means of these grooves each rib engages such screw or-bolt at two points, and therefore prevents its displacement from a true axial position in the shield. In the construction which l have shown the bolt-engaging abutments or ribs are formed by the sides of the square axial cavity D acting in conjunction with the longitudinal slots formed in my shield. It is manifest that the internal ribs or bolt-engaging projections of relatively small area could be formed upon the interior of such a shield in any other manner. The number of such projections might also vary, as well as their form or contour, without destroying their function in forming internal ribs into which the bolt may press readily and force the yielding material of the shield outward with a comparatively gentle action. The exact form of my internal cavity might be Varied considerably, although it is desirable in all cases to have the radial thickness of the walls of the shield greater at the rear of the shield than at the front portion of the same-that is, the shield may be formed with a body portion which is either cylindrical or tapering and with a corresponding interior cavity; but in order to secure the desirable effect of having a greater expansi- .Y *V V ble action at the rear of the shield than at the Y front of the same the radial thickness of the 7o,Y1 .l walls should be greater at the rear of the shield.

If desired, the exterior surface of my shield may'be made either roughened, as shown, or plain or formed with suitable ribs or corru- Y' Y gations, which may be of any desired size.VY l Such a ribbed exterior vsurface in a similar shield is disclosed in my Patent No. 575,282, dated January 12, 1897. Y Y' Y It is of course manifest that the number of8o longitudinal slots might be varied, forming aYYY different number of members or sections 13,12. or, indeed, such slots might be omitted alto-A gether if the material ofl which the shield isV f *i composed is sufficiently soft and yielding to)V Y, l expand with the required ease. Y V 'Y f The exact scope of myinvention is set forth in the appended claims. l V' Y What is claimed as new isi` l. An expansion-shield consisting of a tu?" Y bular block longitudinally slotted for the greater part of its length forminglongitudiual internal ribs and having an interior cavity j formed therein so that its inner surface en* gages a screw inserted intosaid blockY through only a small portion of the periphery of saidVV`V ai' y screw and such innersurface being threadedvr 1 by said screw. V y Y 2. An expansion-shield, consisting of a t'ul bular `block longitudinally slottedfor part of 11 co Y its length and having interior projections ar ranged to form the seat for a bolt inserted i into said block. Y 'g 8. An expansion-shield, consisting of a tu-jrf. bular block having a series of longiti1dinal ,;1o5g;Y slots extending along part of thelength of j the block and having interiorprojectionsarn ranged to form a seat for a boltinserted'intoy A,said block. Y Y

4. An expansion-shield, consisting of anV expansible block having a tubularhead, af plurality of sections connected with said headVV and separated from each other by longitudi-k nal slots and provided with interior -projecV-V Y tions having longitudinal grooves along their?. f 'i2 inner edges arranged to form aseatffora bolt inserted into said block. e

5. An expansionshield, consisting Vof Ya block having a tubular head, a plurality ofrfrj.-v sections connected 'therewithand separated n from each other by longitudinal slots and` pro; ,Y vided with interior projections formed by the 'n intersection of the slots to be threaded by aij' screw inserted in 'said block. Y V V V Y Vj. u Y

6. An expansion-shield, consisting of ex- .m5- pansible block having a tubular head, a plu-v Y rality of sections connected therewith andY separated from each other by longitudinalVV Y slots and provided with interior projections, Y there being grooves formed along the inner 13e,Y portions of said projections. .Y n Y 7. An expansion-shield consisting of an integral block having a tapering hole formed j throughout the length of said block and'having a series of interior longitudinal ribs arranged to be engaged by a screw inserted into said hole and to be threaded by said screw.

8. An expansion-shield, consisting ot a tubular block of expansible material having a cavity formed therein to receive a bolt inserted in said cavity and being formed with longitudinal ribs to engage said bolt through only a small portion of the periphery of the saine so as to yieldingly force the expansible material outward.

9. An expansion-shield, consisting of a tubular block longitudinallyslotted throughout a part of its length having a cavity formed therein to receive a bolt and having longitudinal ribs adapted to engage with said bolt throughout a small portion of its peripheral surface.

10. An expansion-shield, consisting of a tubular block longitudinally slotted throughout a part of its length and havinga cavity formed therein adapted to receive a threaded bolt inserted into said cavity, ribs formed upon the slotted portion of said shield and adapted to engage the threads of said bolt.

11. An expansion-shield, consisting of a cylindrical body of expansible material provided With a tapering cavity and interior ribs or projections adapted to be readily engaged by the threads of a bolt inserted into said cavity.

12. An expansion-shield, consisting of a cylindrical body of expansible material having a tapering axial hole of substantially square cross-section passing throughout the length of said body and having interior ribs arranged to be engaged by a bolt inserted in said hole. Y

13. An expansion -shield consisting of a longitudinally-slotted tubular block of soft material having interior longitudinal ribs arranged to have threads cut thereiny by a screw inserted in said block to form a seat for said screw.

14. An expansion shield, consisting of a block of expansible material having a tapering hole formed throughout the length of the block so as to form Walls of varying thickness from end to end of said block, said block being slotted longitudinally throughout a part of its length Where the Walls are thickest and said block having a series of interior ribs or projections.

15. An expansion-shield, consisting of a cylindrical body of expansible materialhav-- ing a roughened exterior longitudinally slotted throughout a part of its length formed with a tapering axial hole of substantially square cross-section extending from end to end of said body, said ribs forming a series of interior grooved projections in connectionl with said axial hole.

16. An expansion-shield consisting of a block of yieldable material having an interior cavity and being formed with longitudinal interior ribs to be engaged by a screw inserted in said block to form a seat for said screw.

17. -An expansion shield, consisting of a block of suitable material having an interior cavity formed therein, the Walls of said block being of varying thickness throughout the length of said block, there being longitudinal interior ribs formed on said block to form a,

Witnesses:

.Tassin B. KAY, HARRY L. DUNCAN. 

